Indoor noise:
-Talk to a contractor to see what type of modifications can be done to reduce noise
–Sound proof paneling, double paned windows, plantation shudders..
-Non scary, non irritating white noise
–Fans, air purifiers, dehumidifiers, music (especially “Through a Dog’s Ear“)
— And same as above, help the dog feel better about neighbor noise

Note: there is no need to punish a dog for being upset about neighbor noise
– startle methods such as the “can of pennies” can make a dog more frantic, more stressed…
Why punish our dogs for something that the neighbor is doing?

Also ask your vet about calming aids that might help your dog relax when the neighbors are noisy